1. Field of the Invention
The present invention relates to an IC module and a junction structure thereof.
2. Description of the Related Art
The tape carrier package of a TAB (tape automated bonding) type is known as an IC module of such an arrangement wherein an IC chip is mounted on a film substrate. The IC module of this category is of a structure comprising, as shown in FIG. 5, a plastic film substrate 1 which has a slit-like opening 2 at a folding part thereof, wiring leads 3 of some metal such as copper bridging the opening 2 provided in the surface of the film substrate 1, and an IC chip coupled to the wiring leads 3. More precisely, the IC chip 4 is arranged in a device hole (omitted from being illustrated) which is provided in the film substrate, and coupled to internal ends of the wiring leads 3 projecting in the device hole.
Where the IC module undergoes a mounting structural restriction over the coupling to a liquid crystal display panel 5 for example, the film substrate 1 is folded at a part where the opening 2 exists, with an outer end of each wiring lead 3 coupled to a connection terminal of the liquid crystal display panel.
Such an IC module as remarked above is confronted with the problem giving rise to an inconvenience that the wiring leads 3 are subject to breakage due to the external forces stemming, respectively, from pulling, bending and so forth which the wiring leads 3 suffer since the film substrate 1 is folded, together with the wiring leads 3 at the part where the opening is located which the wiring leads 3 bridge. Of particular note in this regard is a fact that the case where the wiring leads 3 are arranged in a narrow inter-lead gap pattern used to entail such a trouble that bending the substrate concurs with subsequently deforming the wiring leads 3, whereby adjacent ones of the wiring leads 3 are brought into a contact with each other, with shortcircuiting to follow as a result.